Usage and dosage reference and detailed explanation of treatment effect of lung cancer drug Pozitinib

Introduction: Pozitinib is mainly used to treat non-small cell lung cancer (NSCLC), breast cancer, gastric cancer and head and neck cancer. For NSCLC patients carrying EGFR exon 20 insertion mutations, pozitinib has shown significant efficacy, with interim results from a phase 2 clinical trial showing an objective response rate of 73%. This article mainly talks about the usage and dosage, mechanism of action, therapeutic effect, etc. of pozitinib.

Usage and Dosage

Standard dosage regimen

Recommended dosage: 16 mg once a day.

Taking time: Take with food or on an empty stomach, continuously.

Dose adjustment

If the patient cannot tolerate the adverse reactions caused by the standard dosage regimen, the dose can be adjusted.

First dose reduction: reduce to 14mg once a day.

Second dose reduction: If the dose of 14 mg is still intolerable, further reduce to 12 mg once a day.

Intermittent dosing

For patients who wish to use intermittent dosing, you can choose the following plan:

24mg dosage plan: Take 24mg for three days, and then stop taking the drug for one day.

Dose adjustment: If the 24 mg dose causes intolerable adverse reactions, it can be reduced to 18 mg for three consecutive days and then discontinued for one day.

Mechanism of action

Targeted inhibition: Pozitinib can specifically inhibit multiple members of the human epidermal growth factor receptor (HER) family, including EGFR (epidermal growth factor receptor), HER2 and HER4.

Block signaling: By irreversibly binding to HER family tyrosine kinase receptors, pozitinib blocks the signaling pathways of these receptors, thereby slowing or stopping the proliferation of tumor cells that overexpress these receptors.

Induction of apoptosis and cycle arrest: Pozitinib can induce the mitochondrial pathway in HER2-amplified gastric cancer cells, leading to apoptosis and G1 cell cycle arrest.

Synergistic effect: Pozitinib and chemotherapy drugs can exert a synergistic effect in HER2-induced and HER2-non-amplified gastric cancer cells.

Anti-tumor activity: Pozitinib has shown excellent anti-tumor activity in a variety of EGFR- and HER-2-dependent tumor xenograft models.

Targeting specific mutations: Pozitinib is specifically targeted at patients with non-small cell lung cancer (NSCLC) who carry exon 20 insertion mutations of the EGFR and HER2 genes. Such patients are insensitive to traditional EGFR-targeted drugs.

Therapeutic effect

For NSCLC patients carrying EGFR exon 20 insertion/mutation (EXON 20 insertion/mutation), the interim results of the Phase 2 clinical trial of pozitinib showed that the patient's objective response rate (ORR) reached 73%. This result is significantly better than the efficacy of traditional EGFR tyrosine kinase inhibitors in patients with exon 20 mutations (ORR is only about 8%).

In a phase II clinical trial called ZENITH20, pozitinib showed efficacy in patients with metastatic NSCLC with EGFR or HER2 exon 20 mutations. Cohort 5 of the trial, which looked at 40 patients, showed reduced toxicity when they took twice daily. The incidence of toxicity was 31% for those receiving the 16 mg daily dose and 21% for the 8 mg twice daily dose.

The ZENITH20 trial also studied 79 patients with metastatic NSCLC with EGFR exon 20 mutations who received 16 mg of pozitinib daily and found that their tumor activity improved, suggesting that tumor activity in the HER2 population also improved.

As a new type of targeted drug, pozitinib provides a new treatment option for NSCLC patients carrying specific HER family mutations. Pozitinib has not been approved for marketing in China, so you need to consult a professional doctor before use and follow the doctor's instructions.